JPS63103815A - Apparatus for continuous production of sio fine powder or such - Google Patents

Abstract

PURPOSE:To obtain SiO powder in high efficiency, by using a continuous process maintained to a reduced pressure from the charge to the delivery in the heat- treatment of an SiO2 oxide powder to generate SiO vapor and the recovery of condensed SiO powder. CONSTITUTION:A raw material mixture 8 composed mainly of an SiO2 oxide powder and containing a carbon-containing component or metallic silicon powder is continuously charged through hoppers 4a, 4b into a muffle 2. The mixture is heated in the muffle 2 with a heater 10 in a non-oxidizing atmosphere having reduced pressure to effect the reaction of SiO2 with carbon or silicon in the raw material mixture and generate SiO vapor. At the same time, a non-oxidizing gas is introduced into the muffle 2 through gas inlet ports 17, 18 and the generated SiO vapor is condensed in a gaseous phase. At the same time, the condensed product is transferred to SiO powder recovery chambers 11, 12 via transfer pipes 8, 9 heated with the heater 10 and is recovered in the form of SiO powder.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to the continuous production of SiO fine powder, etc.
Mainly fine amorphous 810 of 0.1 μm or less
This invention relates to an apparatus for continuously producing powder and also obtaining ZrO2 powder etc. as a secondary product.

Such a Sin powder is Si3N4. It can be used as a raw material for fine ceramic powder such as SiC, which has been attracting a lot of attention in recent years.In particular, the SiO powder obtained with the device of the present invention is as fine as 0.1 μm or less, is extremely active, and is useful for ceramics. It has very high industrial value as a raw material for synthesis.

(Prior art) As a conventional technology related to the production of SiO fine powder, etc., a mixture of so-called SiO□ and carbon, or 5i02 and metal Si is heated at 1500°C or higher, as disclosed in Japanese Patent Publication No. 59-50601. By reacting at high temperature and under reduced pressure to generate SiO vapor, and by reducing and carbonizing the slo vapor or injecting it into a reduced pressure oxygen cloud atmosphere by adiabatic expansion, amorphous particles with a particle size of 0.1 μm or less are produced. BACKGROUND ART A method for obtaining fine SiO powder and an apparatus therefor are known.

(Problems to be Solved by the Invention) The conventional technology related to the production of SiO fine powder, etc. described above is good for small-quantity production, but when producing large quantities, it is difficult to use a conveying pipe for conveying SiO vapor. may be blocked by condensed SiO.

Moreover, the nozzle for ejecting through adiabatic expansion may be eroded by the SiO vapor and no longer function as a nozzle, or the reactant may accumulate in the nozzle and become clogged, so this technology has no real meaning. However, it cannot be said that it provides manufacturing equipment suitable for industrialization and mass production.

Therefore, the present inventors have developed a manufacturing technology that can overcome the problems of the above-mentioned conventional techniques for manufacturing SiO fine powder, etc., and is suitable for mass production of extremely fine SiO fine powder of 0.1 μm or less. , previously filed a patent application in 1986-1656.
I proposed it as No. 76. To introduce the gist of this invention, firstly, a mixture of SiO□-based raw materials and carbon-containing materials and/or metal silicon powder is heated at 1300 to 2000°C in a non-oxidizing atmosphere with a reduced pressure of 0.1 atmosphere or less. Producing SIO fine powder of 0.1 μm or less by performing heat treatment in a temperature range to generate SiO vapor, condensing the SiO vapor with the non-oxidizing gas, transporting it, and recovering it as SiO powder. , Second, a mixture of SiO□-based raw materials and carbon-containing materials and/or metal silicon powder is heat-treated in a temperature range of 1300 to 2000°C in a non-oxidizing atmosphere reduced to 0.1 atmosphere or less to form SiO generating steam, condensing the SiO vapor with the non-oxidizing gas, transporting it, and recovering it as SiO powder, while also separately recovering the remainder of the raw material subjected to the vacuum heat treatment; and thirdly, the above-mentioned The aim was to provide manufacturing equipment suitable for each manufacturing method.

The purpose of the present invention is to propose a continuous process in which processes from charging to discharge are unified using a reduced pressure system regarding the apparatus for producing SiO powder, etc. proposed in Japanese Patent Application No. 165676/1987 proposed by the present inventors. The object of the present invention is to provide an apparatus that can continuously and efficiently produce not only SiO fine powder but also zirconia powder.

(Means for Solving the Problems) Aiming to develop an apparatus that can meet the above-mentioned demands, the present inventors have developed a raw material of 5iO7 powder or 5i02-based oxide raw material, carbon-containing material, and/or metal silicon powder. As a result of various studies on devices for continuously and efficiently producing by-products such as 310 fine powder and 2rO7 powder from a mixture, it was found that an effective means that incorporates the form of a vertical furnace and has the following points as its main structure. I found out something.

A raw material mixture mainly consisting of SiO□-based oxide powder,
A device that generates SiO vapor by heat treatment in a reduced pressure non-oxidizing atmosphere, and then condenses this SiO vapor in the gas phase and recovers it as SiO powder, with a raw material supply system and a by-product at the top and bottom, respectively. In the main reaction tower connected to the extraction system, there is a Matsufuru whose vertical direction functions as a pre-soaking zone, a soaking zone, and a cooling zone, and from the central soaking zone of the Matsufuru there is a pipe for conveying SiO vapor that protrudes horizontally. and Si at the other end of the conveying pipe.
An S having a configuration in which an O powder uncollected chamber is provided, and a heating element is provided around the matsufuru and the conveying pipe.
Continuous production equipment for iO fine powder, etc.

Next, the above device will be specifically explained. Figure 1 shows
This is a typical configuration example of the present invention, in which the process from supplying raw materials to discharging by-products, which are reaction residues of the main product, is in the form of a vertical furnace, and the main reaction tower has a pre-heating zone, a soaking zone, The SiO fine powder to be recovered in the present invention is a cooling zone, and the SiO fine powder to be recovered in the present invention is distributed horizontally from the soaking zone to one or more, more preferably a plurality of S
iO vapor (equipped with a general purpose vibrator).

In the figure, the reference numeral 1 is a main reaction tower which is a vertical reduced pressure heat treatment furnace, and in the axial direction (vertical direction) inside this tower, there are a pre-heating zone A, a soaking zone B, and a cooling zone C from the top. It is arranged so that the Matsuful 2 that is in the hole passes through it. This Matsuful 2
A raw material supply system consisting of upper and lower raw material hoppers 4a and 4b with two charging valves 3a and 3b interposed is connected to the outside of the upper end column, and outside the lower end tower of the Matsuful 2,
A by-product extraction system consisting of a by-product extraction chute 5, a seal valve 6, and a by-product recovery chamber 7 is connected.

Inside the main reaction tower 1, there are areas around the Matsufuru 2, especially a pre-soaking zone A and a soaking zone B, and a soaking zone B of the Matsufuru 2.
A heating zone 10 is disposed around a pipe 8.9 for discharging the generated Sin vapor that protrudes horizontally from the top.

SiO powder unrecovered chambers 11.12 are airtightly connected to the free ends of the pipes 8.9 for conveying the steam, and a SiO powder unrecovered chamber 11.12 is connected to the lower part of the recovery chamber 11.12 for extracting the SiO fine powder to the outside. A discharge valve 13 is provided for this purpose. Note that 14. The bag filter 115 is an exhaust pipe, and 16. is a discharge valve.

At the lower end of the Matsufuru 2, there is a movable opening/closing stopper 21 for supporting the raw material mixture filled inside.
When this stopper is evacuated, the by-products remaining after the Sin vapor remaining in the Matsufuru 2 has been extracted fall and pass through the seal valve 6 and the by-product recovery chamber 7 to collect the by-products such as zirconia powder. It can be extracted.

Reference numerals 17 and 18 in the figure indicate non-oxidizing gas injection ports, which become carrier gas for the Sin vapor, and are finally sucked into a vacuum evacuation device using a Lochley pump or the like through a filter and exhaust piping 15. Ru.

Further, the above-mentioned Matsufuru 2 is effective in protecting the heating element 1O from the generated SiO vapor, 19 is a pipe for exhausting the space of the heating element, and 20 is a gas inlet for backwashing the back filter.

In the above description, a preferred example is a type in which the heating element 10 is a rod-shaped graphite material, a type in which the furnace body constituting the main reaction chamber is provided with a water cooling jacket, a Matsufuru 2 and a Si01M delivery pipe 8. , 9 are graphite-based, S
It is preferable to use an iC-based material, and it is also preferable to use a graphite-based heat insulating material for the furnace wall.

(Function) Now, the specific details of the method for manufacturing SiO fine powder using the above-mentioned manufacturing apparatus adopted to solve the problem will be explained below.

The SiO□-based raw material powder used in the manufacturing apparatus of the present invention is not particularly limited, but fine powder is preferable in order to efficiently generate SiO vapor.

Furthermore, in order to maintain the resulting SiO fine powder at a high purity, it is preferable that the 5i02 powder used be of high purity. For example, it is manufactured by reacting natural high-purity quartz powder or water glass with acid or carbon dioxide gas: S by the so-called wet method.
iO□ powder is suitable. In addition, oxide powder containing 5in2 is effective as a raw material. For example, SiO2
Examples of oxides containing zircon (ZrO7/SiO2
) powder, mullite (3A1203 2SiO2) powder, wollastonite (CaO-5in2) powder, etc. Furthermore, oxide glass powder containing such components can also be used.

A carbon-containing substance is mixed with the SiO□-based raw material, and the carbon-containing substance may be petroleum coke, coal pitch, carbon black, various organic resins, or the like. Further, the same effect can be obtained even if metal silicon powder is used instead of the carbon-containing substance, and the same effect can be obtained even if the carbon-containing substance and the metal silicon powder are mixed at the same time.

These raw material mixed powders are continuously charged into the Matsufuru 2 from the raw material hopper 4a via the charging valves 3a and 3b to the lower raw material hopper 4b which serves as a gas exchange chamber, and are filled into the Matsufuru 2. The state will be as follows.

Next, a mixed powder of Si[l□-based raw material and carbon-containing material and/or metal silicon powder filled in Matsufuru 2,
Or those molded bodies are held under a reduced pressure of a non-oxidizing atmosphere of 0.1 atmosphere or less, and the heating element 10 acts to generate a temperature of 1300
It undergoes a heat treatment to a temperature range of ~2000°C. The atmospheric pressure within the Matsufuru 2 is preferably set to 0.1 atmosphere or less in order to efficiently generate Sin vapor.

When the heat treatment is performed in this manner, since the SiO2 powder and the carbon-containing material or the metal S1 powder are mixed, reactions proceed according to the following equations (1) and (2), respectively, and S
in steam is generated.

Sin□(Cs)+C(s) -Sin(g)+CO
(g) −(1)SiO□(j!, s)+5i(s)
= 23iO(g) ・” (2)(
The thermodynamic temperature required for the reaction of formula 1) to proceed continuously at 1 atm -q, m is 1750°C or higher. However, if the process from supplying raw materials to discharge is performed in a reduced pressure atmosphere as described above, the thermodynamic temperature required to proceed with the reaction of equation (1) is, for example, 1640°C under 0.1 atm. ,0. Under O1 atmosphere, the temperature is 1540℃, and if the pressure is lowered by one order of magnitude, the heat treatment temperature required for the reaction is 100℃.
It decreases around ℃. From this (1).

If the reaction of formula (2) is performed under reduced pressure, heat treatment can be performed at low temperature and in a short time, and SiO vapor can be efficiently generated.

Although 810 steam is generated in the Matsufuru 2 of the main reaction tower under the vacuum heat treatment conditions as described above, the apparatus of the present invention also generates non-oxidizing gas from the gas inlets 17 and 18 for the vacuum heat treatment during the heat treatment. introduced into the furnace, and the S generated in the furnace
While the iO vapor is condensed in the gas phase, it is conveyed to the SIO powder uncollected chamber 11 through the conveying pipe 8 which is heated and kept in an airtight condition, and is recovered as SiO powder.

At this time, N2. 8r, co,
A gas such as 82 is preferred.

There are three purposes for introducing such a non-oxidizing gas from the outside.

■ Efficiently transport and remove SiO vapor from the object to be heat treated.

■ By rapidly cooling the SIO vapor, Qi is rapidly condensed from the eyes and the SiO is turned into ultra-fine powder.

■ The generated SiO fine powder is conveyed to the powder recovery device by air current.

According to Japanese Patent Publication No. 59-50601, which is a prior art related to the manufacturing method of this SiO fine powder, SiO vapor is injected from the nozzle at a speed of 0.6 to several meters using a tapered nozzle or a wide-spread nozzle, and It states that by expanding and rapidly cooling, SiO fine powder is obtained. However, according to the device of the present invention, the generated SiO vapor can be directly condensed in the gas phase by simply introducing non-oxidizing gas into the furnace from the outside without such complicated manufacturing technology and manufacturing equipment. - It is possible to transport and easily produce SiO fine powder.

The purpose of injecting a non-oxidizing gas is as mentioned in (1) to (3) mentioned above, but regarding the process of generating SiO powder from SiO vapor, the injected non-oxidizing gas is It is believed that fine SiO powder is produced by condensation in the gas phase due to the rapid cooling action of the oxidizing gas. Then, the SiO fine powder generated in the above process is carried by the non-oxidizing gas airflow and transported to the SiO powder unrecovery chamber 11, and then the discharge valve 13. 16, while the gas is passed through the bag filter 14 to the exhaust pipe 1.
Exhaust through 5.

On the other hand, by-products such as zirconia powder are taken out from the lower end of the Matsufuru 2 while moving the stopper 21 back and forth.

(Example) SiO2 containing 199.5% SiO2\A powder and Zr
From zircon powder and coal pitch whose total content of O□ and SiO□ is 99.0%, the mixing molar ratio (C/5IG2) of SiO□ and the amount of fixed carbon in the coal pitch is 1.0. were uniformly mixed to obtain a raw material mixture. These raw material mixtures were heat-treated using the apparatus shown in FIG. 1 at the temperature and pressure cover turn shown in FIG. 2. As a result, S
SiO with a particle size of 0.1 μm or less is collected from the iO powder uncollected chamber.
A large amount of fine powder was obtained with a yield of 70% or more.

On the other hand, in the by-product recovery room, high-purity zirconia powder of 99% or higher was produced in large quantities at a high yield.

(Effects of the Invention) As described above, according to the cost-producing apparatus of the present invention, from a raw material mixture consisting of a 5i02-based raw material and a carbon-containing material or a metal silicon powder, only SiO fine powder and SiO fine powder and raw material are mixed. The oxide powder (for example, zirconia powder) that is a component contained in the product can be manufactured by continuously and efficiently distinguishing and taking out fW.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the apparatus of the present invention, and FIG. 2 is an explanatory diagram of a heat pattern during heat treatment employed in an example. ■...Main reaction tower 2...Matsuful 3a, 3
b...Charging valve 4a...Upper raw material hopper 4b...Lower raw material hopper 5...Discharge chute 6...Seal valve 7...
・By-product recovery room 8.9...Transport pipe (Sin vapor) lO...Heating element 11.12...SiO powder uncollected room 13
, 16...Discharge valve 14, 14'...Valve filter 15...Exhaust pipe 17, 18...Gas inlet (non-oxidizing) 19...Exhaust pipe 20...Reverse Cleaning gas inlet 21...stopper

Claims (1)

[Claims] 1. Si
This is a device that generates O vapor, then condenses this SiO vapor in the gas phase and recovers it as SiO powder, and has a main reaction tower with a raw material supply system and a by-product extraction system connected to the top and bottom, respectively. , the vertical direction is the preparatory zone,
A muffle is provided that acts as a soaking zone and a cooling zone, and from the central soaking zone of this muffle, SiO protrudes horizontally.
SiO fine powder having a structure in which a steam conveying pipe is provided, a SiO powder recovery chamber is provided at the other end of the conveying pipe, and a heating element is provided around the muffle and the conveying pipe. etc. continuous manufacturing equipment.